Reference for Eruvin 203:17

אמר רב משום רבי חייא וילון מותר לנטותו ומותר לפורקו בשבת

What is the reason? One is thereby merely adding to an occasional tent<span class="x" onmousemove="('comment',' The arches.');">⁵³</span> which is perfectly legitimate.<span class="x" onmousemove="('comment',' Lit., 'it is considered well or right'.');">⁵⁴</span> R'Huna possessed some rams that needed the shade in the daytime and the open air at night.<span class="x" onmousemove="('comment',' On a weekday this was easily arranged by spreading a mat on the top of the shed in the morning and by rolling it up in the evening; but on the Sabbath the question of tent building arose.');">⁵⁵</span>

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